JP6098994B2 - Heat pump hot water supply system - Google Patents

Description

  The present invention relates to a heat pump hot water supply system, and more particularly, to a heat pump hot water supply system configured to change the temperature of hot water stored in a hot water storage tank according to an estimated amount of heat demand.

  The heat pump hot water supply system has a learning ability based on past heat demand, predicts the generation time of heat demand and the amount of heat demand in the future relatively finely, and uses the heat pump of the heat amount corresponding to the predicted heat demand. There is a system in which the operation generated by operation and stored in the hot water storage tank is performed as soon as possible just before the generation time of heat demand. Conventionally, unlike such a method, for example, by operating a heat pump using nighttime power, hot water corresponding to the heat demand for one day is generated in a lump and then stored in a hot water storage tank. However, the former can reduce the heat radiation loss from the hot water storage tank as compared with the above. Further, the amount of hot water stored in the hot water storage tank can be more accurately met with actual heat demand. Therefore, it is preferable for suppressing the occurrence of excess hot water or shortage of hot water. Furthermore, as a hot water storage tank, it is not necessary to use a size that can store hot water corresponding to the heat demand for one day, and a small hot water storage tank may be used, and the equipment cost can be reduced. .

  On the other hand, in order to increase the COP (coefficient of performance) of the heat pump, it is preferable to set the temperature of the hot water supplied by the heat pump to a relatively low temperature of about 50 ° C., for example. However, if the hot water temperature is uniformly set to such a low temperature, a shortage occurs when there is a large amount of heat demand. For this reason, conventionally, when heat demand is predicted, when the amount of heat demand is large and exceeds a predetermined threshold, the hot water temperature is set to a high temperature of about 65 ° C., for example. .

  However, in the past, there was room for improvement as described below.

  That is, in the past, for example, when it is predicted that a plurality of heat demands occur at a certain time interval, the amount of the first heat demand is relatively small, and the amount of the next heat demand is considerably large, The hot water storage temperature for the first heat demand is set to a lower temperature (for example, 50 ° C.), and the hot water storage temperature for the next heat demand is set to a higher temperature (for example, 65 ° C.). However, with this setting, if the actual heat demand of the first heat demand is less than expected and the hot water at a lower temperature in the hot water storage tank becomes surplus, the next heat demand will be met. Even if it is attempted to increase the amount of hot water in the hot water storage tank to cope with it, it may be difficult to increase the amount of hot water in the hot water storage tank due to the presence of the low temperature hot water described above. In this case, the amount of hot water in the hot water storage tank is insufficient for the next heat demand, which is not appropriate. Therefore, it is desirable to prevent such a situation from occurring.

Japanese Patent Laid-Open No. 5-118660 Japanese Patent No. 4688586

The present invention has been conceived under the circumstances as described above, and is a heat pump hot water supply capable of improving the energy efficiency of the entire system and preventing problems such as lack of hot water from occurring. The challenge is to provide a system.

  In order to solve the above problems, the present invention takes the following technical means.

  The heat pump type hot water supply system provided by the present invention stores a heat pump, a hot water storage tank that stores hot water heated by the heat pump, and can supply the hot water to a predetermined outlet or heat load, and to the past heat demand. Based on the learning ability, predicting the future heat demand generation time and heat demand, and operating the heat pump before the predicted heat demand occurs to supply the hot water with the heat quantity corresponding to the heat demand to the hot water storage tank. Control means for executing control for storing, and when the hot water corresponding to the heat demand is stored in the hot water storage tank and the heat demand is equal to or less than a predetermined threshold, While the hot water storage temperature corresponding to this heat demand is set to a predetermined first temperature, and the amount of heat demand exceeds the threshold, the hot water storage temperature is set to a second temperature higher than the first temperature. A heat pump hot water supply system configured to execute control for temperature, wherein the control means is configured to control the heat demand when a heat demand for a hot water storage temperature as the second temperature is predicted. When it is predicted that there is another heat demand within a predetermined time before the occurrence, the hot water storage temperature corresponding to the other heat demand is set as the second temperature regardless of the amount of the heat demand. It is characterized by being configured to execute control.

According to such a configuration, the following effects can be obtained.
That is, in the case where heat demand with the hot water storage temperature being the second temperature (higher temperature) is predicted, if there is another heat demand within a predetermined time before the occurrence of this heat demand, the amount of heat demand is small. Even if the hot water storage temperature is sufficient at the first temperature (lower temperature), the hot water storage temperature corresponding to this other heat demand is set as the second temperature. Therefore, even if the amount of other heat demand described above is smaller than the predicted heat demand amount and there is a surplus of hot water, the hot water remaining in the hot water storage tank becomes the second temperature (higher temperature). For this reason, it is possible to store hot water with a necessary amount of heat in the hot water storage tank for the heat demand generated thereafter. As a result, unlike the prior art, it becomes possible to prevent hot water shortage.
On the other hand, in the present invention, except for the cases described above, basically, when the heat demand is equal to or less than a predetermined threshold, the hot water storage temperature is set to the first temperature (lower temperature). In addition, the coefficient of performance of the heat pump can be increased and energy efficiency can be improved.

  In the present invention, preferably, the predetermined time is set to a variable value, and it is predicted that another heat demand is frequently generated before the heat demand at which the hot water storage temperature is the second temperature is generated. In some cases, it is configured to be set to a longer time than otherwise.

  According to such a configuration, when it is predicted that the frequency of occurrence of another heat demand is high before the heat demand at which the hot water storage temperature is the second temperature is generated, The corresponding hot water storage temperature is easily set to the second temperature. Therefore, it is possible to make it difficult for hot water shortages to occur when the frequency of heat demand is high. On the other hand, when the frequency of heat demand is low, the hot water storage temperature is suppressed from being set to the second temperature forcibly, so that excessive hot water is appropriately avoided. Is done.

In the present invention, preferably, it further includes an auxiliary heat source device capable of heating hot water supplied from the hot water storage tank to the predetermined outlet or heat load in the middle thereof, and the control means has a heat demand amount. Even when the threshold value is exceeded, compared to the case where the hot water storage temperature is set to the second temperature, the case where the hot water storage temperature is set to the first temperature and then the insufficient heat amount is compensated by the auxiliary heat source device. When it is determined that the energy efficiency is high, the hot water storage temperature is set to the first temperature.

  According to such a configuration, the energy efficiency of the hot water supply system including the auxiliary heat source device can be increased. In addition, when hot water runs out in the hot water storage tank, it is possible to appropriately cope with the auxiliary heat source machine.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is a schematic explanatory drawing which shows an example of the heat pump type hot water supply system which concerns on this invention. It is a flowchart which shows an example of the operation processing procedure of the control part which the heat pump type hot-water supply system shown in FIG. 1 comprises. (A), (b) is explanatory drawing for understanding a part of process performed by the control part which the heat pump type hot-water supply system shown in FIG. 1 comprises.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  The heat pump hot water supply system A shown in FIG. 1 is configured by combining a heat pump 1 and a hot water storage tank unit U.

The heat pump 1 is the same as a conventionally known one. For example, an evaporator 10, a compressor 11, and a condenser that absorb heat from air taken in using a fan 10 a into a circulation path of a refrigerant such as CO ₂ . A heat exchanger 12 for heating hot water and an expansion valve 13 are provided.

  The hot water storage tank unit U includes a hot water storage tank 2, an auxiliary heat source device 3, and a control unit 4.

  A lower part and an upper part of the hot water storage tank 2 are connected to the heat exchanger 12 of the heat pump 1 via the piping parts 50a and 50b. When the circulation pump P1 provided in the pipe section 50a is driven, hot water flows through the paths indicated by arrows N11 to N13, and the hot water flowing out from the lower portion of the hot water storage tank 2 is heated by the heat exchanger 12, and then stored in hot water. It is returned to the upper part in the tank 2. As a result, hot water is stored in the hot water storage tank 2.

  Connected to the lower and upper portions of the hot water storage tank 2 are a water inlet pipe 61 having a water inlet 61a and a hot water outlet pipe 62 having a hot water outlet 62a. When the hot water tap 90 piped to the hot water outlet 62a is opened, the hot water in the hot water storage tank 2 flows out into the hot water outlet pipe 62 due to the water pressure in the hot water storage tank 2, and enters the hot water tap 90 from the outlet 62a. Supplied towards. In addition, although omitted in the drawings, in the heat pump hot water supply system A of the present embodiment, bath hot water for performing hot water filling in a bathtub or the like is also possible.

The auxiliary heat source unit 3 is used for heating hot water when the amount of hot water in the hot water storage tank 2 is insufficient, and the configuration thereof is the same as that of a gas instantaneous water heater, for example. Specifically, the auxiliary heat source unit 3 is configured such that the burner 30 and the heat exchanger 31 are accommodated in the can 32 and hot water supplied to the heat exchanger 31 can be quickly heated by the burner 30. Yes. The incoming water side piping part 70a of the auxiliary heat source unit 3 is connected to the upper part of the hot water storage tank 2 via the pump P2 and the three-way valve V1. The hot water side piping part 70b of the auxiliary heat source device 3 is connected to the hot water pipe 62 via a three-way valve V2. For this reason, when the hot water is discharged from the hot water outlet 62a toward the hot water tap 90, the hot water heated by the auxiliary heat source device 3 is switched to the hot water outlet 62a by switching the three-way valve V2, as indicated by arrows N21 and N22. Can be supplied.

  A heat exchanger 92 is provided in the pipe part 71 branched and connected to the hot water side pipe part 70b of the auxiliary heat source unit 3. The heat exchanger 92 is one of heat loads, and is for heating a heat medium for the heating terminal 91 such as a floor heating device. The heat medium can circulate between the heat exchanger 92 and the heating terminal 91 by driving the pump P3. Note that the three-way valves V1 and V3 shown in FIG. 1 are connected via a pipe portion 63, so that hot water that has passed through the heat exchanger 92 and reaches the three-way valve V3 is supported without going through the hot water storage tank 2. It can be sent again to the heat source unit 3 and heated.

  The control unit 4 corresponds to an example of a control unit referred to in the present invention, and is configured using a microcomputer or the like. The control unit 4 executes operation control and data processing of each part of the hot water storage tank unit U, and also performs overall operation control of the heat pump hot water supply system A in cooperation with a control unit (not shown) of the heat pump 1. . A remote controller 8 is communicatively connected to the control unit 4. The remote controller 8 has a data display unit 80 and a plurality of operation switches 81. By operating these operation switches 81, for example, about the start of operation of the heating terminal 91 or hot water filling in a bathtub, etc. Timer reservation is possible.

  The control unit 4 has a learning capability for predicting future heat demand based on past heat demand (hot water supply operation results). Since such learning ability itself is known, it is omitted. The prediction of heat demand in the present embodiment is performed in units of relatively short time such as 1 hour (10:00 to 11:00, 11:00 to 12:00, etc.), and when heat demand occurs, Heat demand is predicted. In making this prediction, circumstances such as a bath hot water reservation and a heating operation reservation are also taken into consideration. The prediction target period is basically limited to a predetermined time from the current time, for example, a period from the current time to 9 hours ahead. When the heat demand is predicted, the control unit 4 is as close as possible to the predicted heat demand generation time so that the hot water storage operation to the hot water storage tank 2 is in time by the time when the heat demand is predicted to occur. Then, by starting the operation of the heat pump 1, control is performed to store the hot water in the amount of heat corresponding to the heat demand in the hot water storage tank 2. The hot water storage temperature at that time includes a lower first temperature T1 (for example, 50 ° C.) and a higher second temperature T2 (for example, 65 ° C.), and one of these is selected. However, a specific procedure of the selection process will be described later.

  Next, the operation of the heat pump hot water supply system A will be described. In addition, an example of the operation processing procedure of the control unit 4 will be described with reference to the flowchart of FIG. 2 and FIG.

  First, the control part 4 repeatedly performs the process which estimates the future heat demand based on the past heat demand in a short cycle (S1). This prediction of heat demand is to predict the generation of heat demand from the current time, for example, about nine hours ahead, and specifically, the generation time of heat demand and the amount of heat demand thereof are predicted.

When the heat demand is predicted, the control unit 4 determines whether the heat demand is equal to or less than a predetermined threshold Th. In this determination, when the heat demand is relatively small and is equal to or less than the threshold Th, the hot water storage temperature corresponding to the heat demand is determined to be a first temperature T1 (for example, 50 ° C.) that is a lower temperature ( S2: YES, S3). If the hot water storage temperature is set to a lower temperature, the coefficient of performance of the heat pump 1 can be increased.
The threshold value Th is a value obtained by the following equation, for example.
Th = capacity of hot water storage tank × (first temperature−holding water temperature)
Here, the retained incoming water temperature is the lowest hot water temperature in the hot water storage tank 2 or the hot water temperature in the incoming water piping section near the lowermost part in the hot water storage tank 2.
When the threshold value Th is set to the above-described value, when hot water is stored in the hot water storage tank at the first temperature T1, it is determined whether the heat demand can be covered by the amount of heat of the hot water. In the case where it can be covered (when the heat demand is equal to or less than the threshold Th), the hot water storage temperature is determined to be the first temperature T1. However, in the present invention, it is possible to employ a value different from the above value as the threshold Th.
As the predicted value of the heat demand, for example, a predicted value per two hours can be used instead of the predicted value of the heat demand per hour. In this way, a small amount of heat from 16:45 to 17:00, despite the large amount of heat demand generated from 16:45 to 17:15, for example. It is possible to eliminate the possibility of erroneous determination that the two heat demands, that is, the heat demand and a small amount of heat demand from 17:00 to 17:15, are merely generated.

Unlike the case of step S2: YES described above, when the predicted heat demand is large and exceeds the threshold Th, the control unit 4 basically stores the hot water temperature corresponding to the heat demand as described later. Is a second temperature T2 (for example, 65 ° C.) (S2: NO, S6). However, as a process before that, the controller 4 uses the auxiliary heat source device 3 for the case where the hot water storage temperature is set to the second temperature T2 and the shortage of the hot water storage temperature is set to the first temperature T1. Each energy efficiency is compared with the case of making up. As a result, when it is determined that the latter is more energy efficient, the hot water storage temperature is set to the first temperature T1 (S2: NO, S5: NO, S3). On the other hand, when it is determined that the former is more energy efficient, the hot water storage temperature is set to the second temperature T2 (S5: YES, S6). In the data processing for setting the hot water storage temperature to the second temperature T2, for example, among the predicted heat demand data stored in the storage unit of the control unit 4, the hot water storage temperature is set to the second hot water temperature for the corresponding heat demand data. This is done by turning on a flag indicating the temperature T2.
In addition, when the heat demand is the use of the heating terminal 91, or when the hot water storage temperature is designated in advance as the second temperature T2 for the predetermined heat demand by the remote controller 8, the threshold Th It is also possible to configure the hot water storage temperature to be the second temperature T2 without comparing the amount of heat with the amount of heat demand.

As described above, when the process of setting the hot water storage temperature to the second temperature T2 is executed, whether or not another heat demand is generated within a predetermined time (for example, 3 hours) before this heat demand. Is further determined (S7). In this determination, when another heat demand is generated within the predetermined time, the hot water storage temperature is forcibly set to the second temperature regardless of the amount of the heat demand. T2 is set and a predetermined flag is turned on (S7: YES, S8). The predetermined time described above can be made variable as will be described later.
The hot water storage temperature setting process as described above is repeatedly executed continuously unless a specific end operation such as forcibly turning off the operation of the heat pump hot water supply system A is performed (S4: NO, S1).

More specifically, the process for the hot water storage temperature is a process as shown in FIG.
FIG. 3A shows a state in which two heat demands D1 and D2 are predicted within the range of the heat demand prediction target period (for example, 9 hours) from the current time. One scale on the time axis corresponds to one hour. Both of the two heat demands D1 and D2 have a relatively small amount of heat demand, and the hot water storage temperature is set to the first temperature T1. FIG. 3B shows a case where an appropriate time has elapsed from the time of FIG. 3A, and a new heat demand D3 is predicted after the occurrence time of the two heat demands D1 and D2. ing. This new heat demand D3 has a large amount of heat demand, its hot water storage temperature is set to the second temperature T2, and a flag to that effect is turned on. Accordingly, the heat demand D2 that is predicted to occur within a predetermined time (for example, 3 hours) before the generation time of the heat demand D3 is different from the case of FIG. The temperature is switched to T2, and a flag to that effect is turned on.
In FIG. 3B, the predetermined flag is turned on during the period Pa even though there is no heat demand during the period Pa between the heat demands D2 and D3. For example, if a heat demand occurs during the period Pa, for example, the hot water storage temperature corresponding to the heat demand is useful for setting the second temperature T2 regardless of the amount of heat demand.

  According to the above-described operation control, even if a hot water surplus occurs in the hot water storage tank 2 when the actual heat demand of the heat demand D2 is less than the predicted value and the heat demand D2 is finished, this hot water surplus is generated. The hot and cold water temperature is the second temperature T2, which is a higher temperature. Therefore, it is possible to accurately execute the process of increasing the amount of hot water stored in the hot water storage tank 2 so as to be able to cope with the subsequent heat demand D3. Unlike the present embodiment, if there is a lot of hot water at the first temperature T1, which is a lower temperature, in the hot water storage tank 2, the amount of hot water stored in the hot water storage tank 2 corresponds to the heat demand D3. However, in this embodiment, such a problem can be prevented. When there is a shortage of hot water, the auxiliary heat source unit 3 can be used to prevent the hot water from running out, but the situation where the energy efficiency is lowered by operating the auxiliary heat source unit 3 unexpectedly is appropriately avoided. Is possible.

  The “predetermined time” in step S7 in FIG. 2 can be a variable value. More specifically, the control part 4 has memorize | stored the data of the past heat demand, for example, grasps | ascertains the frequency of the heat demand for every day of the week. For this reason, for example, the day when the heat demand D3 occurs is a day of the week when the frequency of heat demand is high (for example, Sunday), and there is a high possibility that another heat demand will occur before the time when the heat demand D3 occurs. In such a case, the “predetermined time” can be made longer than 3 hours, for example. In this case, the “predetermined time” may be selected in a range of 3 hours to 9 hours, for example, according to the occurrence frequency of heat demand. In this way, for each of many other heat demands that occur prior to the heat demand D3, the hot water storage temperature can be set to the second temperature T2, and it is more reliable to eliminate the hot water shortage. It becomes.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the heat pump hot water supply system according to the present invention can be variously modified within the range intended by the present invention.

  The specific values of the first temperature and the second temperature in the present invention are not limited to 50 ° C. or 65 ° C., and may be other temperatures. In addition, the first temperature and the second temperature are not limited to one kind of temperature, respectively. For example, there are two kinds of the second temperature, 65 ° C. and 70 ° C., and the second temperature is selected. , 65 ° C. or 70 ° C. may be selected. As described above, the specific value of the predetermined threshold in the present invention is not limited to the value described in the above embodiment.

  The heat pump hot water supply system according to the present invention may be configured not to include an auxiliary heat source machine. When the auxiliary heat source unit is provided, the auxiliary heat source unit is not limited to the gas combustion type, but may be an oil combustion type or an electric heater.

A Heat pump type hot water supply system 1 Heat pump 2 Hot water storage tank 3 Auxiliary heat source machine 4 Control unit (control means)

Claims (3)

A heat pump,
A hot water storage tank for storing hot water heated by the heat pump and supplying the hot water to a predetermined outlet or heat load;
Hot water that has learning ability based on past heat demand, predicts the future generation time and heat demand of the heat demand, and operates the heat pump before the predicted heat demand occurs to respond to the heat demand Control means for executing control for storing the hot water in the hot water storage tank;
With
In the case where the hot water corresponding to the heat demand is stored in the hot water storage tank, the control means sets the hot water storage temperature corresponding to the heat demand to a predetermined first temperature when the amount of heat demand is not more than a predetermined threshold. On the other hand, when the amount of heat demand exceeds the threshold, the heat pump hot water supply system is configured to execute control to set the hot water storage temperature to a second temperature higher than the first temperature. There,
In the case where the heat demand with the hot water storage temperature as the second temperature is predicted, the control means, when it is predicted that there is another heat demand within a predetermined time before the occurrence of the heat demand, Regardless of the amount of heat demand, the heat pump hot water supply system is configured to execute control so that the hot water storage temperature corresponding to the other heat demand is the second temperature. The heat pump hot water supply system according to claim 1,
The predetermined time is a variable value, and when it is predicted that the frequency of generating another heat demand is high before the heat demand where the hot water storage temperature is the second temperature is generated, otherwise A heat pump hot water supply system configured to be set for a longer time. The heat pump hot water supply system according to claim 1 or 2,
An auxiliary heat source machine capable of heating hot water supplied from the hot water storage tank to the predetermined outlet or heat load in the middle thereof;
Even if the heat demand exceeds the threshold value, the control means sets the hot water storage temperature to the first temperature and then sets the shortage heat amount to the second temperature compared to the case where the hot water storage temperature is set to the second temperature. A heat pump hot water supply system configured to set the hot water storage temperature to the first temperature when it is determined that the energy efficiency is higher in the case of supplementing with an auxiliary heat source device.

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